Tom Barry Promoter: Prof. Dr. Dirk Hermans; Co-Promoter: Dr, Bram Vervliet

1. Attention to Detail: The Generalization of Extinction Tom Barry Promoter: Prof. Dr. Dirk Hermans; Co-Promoter: Dr, Bram Vervliet University of Leuven, Centre for Learning Psychology and Experimental Psychopathology Background Methods Results Conclusions Treatment of Simple Phobia Despite the effectiveness of exposure therapy in reducing fear to the objects of simple phobias, evidence suggests that fear can return. Post-treatment, the original fear learning may be retrieved and begin to express itself again (Rowe & Craske, 1998). Stimuli Fribbles: ‘A’ (CS) fribbles had only the body in common with ‘B’ (GS) whereas X were a completely different species. Acquisition By the end of Acquisition, there was a significant differential conditioning effect in US expectancy (F(1,37)=308.82, p<.001), SCR (F(1,45)=11.62, p<.05) and FPS (F(1,43)=6.43, p<.05) with no differences between groups (p>.05). GS Extinction Extinction with a GS may be insufficient at preventing fear to a CS; it is no more effective than using a novel stimulus. The Future Research should now ask what the effect of extinction with a GS can have on fear towards other GS. Also, it should explore the role that attention to different stimulus elements has on generalization? A X B Extinction By the final block of Extinction there were no differences between groups on any of the DVs and no differential conditioning effect between CS types. Return of Fear Greater dissimilarity between the original fear event and the stimuli in exposure may prevent generalization of extinction learning to other objects of fear more like the original object of fear. Where treatment stimuli have different features to the original stimulus (generalization stimuli; GS), there may be a possibility that some stimulus features maintain fearful value. Measures Skin Conductance Response (SCR) Fear Potentiated Startle (FPS) Trial-by-trial US expectancy ratings Implications Generalization of Extinction Index of generalization computed: Test Block - Final Extinction Block Significant main effect of extinction condition on the generalization indices for US expectancy (F(2,45)=26.02, p<.001) and FPS (F(2,41)=5.07, p<.05). There was also a positive correlation between the indices for US expectancy and FPS (r=.36, p<.05). Clinical translation Exposure treatment with a stimulus other than the original CS may be insufficient to prevent fear to the CS during subsequent experience. After the original fear learning has been retrieved this may result in full clinical relapse. Design & Procedure (N=48) Acquisition: All groups 6 CS+ with US; 6 CS- no US (A stimuli) Extinction (no US): 3 groups (n=16) - AAA - 12 CS+/- (A) ABA- 12 GS+/- (B) AXA -12 X+/- (completely new stimuli) Test (no US): All groups 3 CS+/- Previous Research The few studies that have assessed extinction with a GS on subsequent fear to a CS, have used US expectancy and skin conductance to assess the return of fear. However, both of these measures are not valence specific and may instead represent the expectation of US and not fear (Vervliet et al., 2005) References Rowe, M. K., & Craske, M. G. (1998). Effects of varied-stimulus exposure training on fear reduction and return of fear. Behaviour Research and Therapy, 36, 719–734. Vervliet, B., Vansteenwegen, D., Baeyens, F., Hermans, D., & Eelen, P. (2005). Return of fear in a human differential conditioning paradigm caused by a stimulus change after extinction. Behaviour Research and Therapy, 43, 357–371. p<.05 A B A A Research question - Is extinction with a GS sufficient to prevent fear to the original CS? p<.001 X Funded as part of the KU Leuven Centre for Excellence - Generalization Research in Ill Health and Psychopathology: Transdiagnostic Processes and Transfer of Knowledge and a Research Foundation - Flanders (FWO) Ph.D Fellowship Grant